package cn.layfolk.nio.groupchat;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;

/**
 * @Author 王津
 * @Date 2020/9/28
 * @Version 1.0
 */
public class GroupChatClient {

    //定义相关的属性
    private final String HOST = "127.0.0.1"; //服务器的ip
    private final int PORT = 6667;//服务器端口
    private Selector selector;
    private SocketChannel socketChannel;
    private String username;


    //构造器，完成初始化工作
    public GroupChatClient() throws IOException{

        selector = Selector.open();
        //连接服务器
        socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1",PORT));
        //设置非阻塞
        socketChannel.configureBlocking(false);
        //将channel 注册到selector
        socketChannel.register(selector, SelectionKey.OP_READ);
        //得到username
        username = socketChannel.getLocalAddress().toString().substring(1);
        System.out.println(username+"is ok...");

    }

    //向服务器发送消息
    public void sendInfo(String info){
        info  = username + " 说："+info;

        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes()));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //读取从服务器端回复的消息
    public void readInfo(){

        try {
            int readChannels = selector.select();
            if (readChannels>0){ //有可以用的通道

                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()){
                    SelectionKey key = iterator.next();
                    if (key.isReadable()){
                        //得到相关的通道
                        SocketChannel sc = (SocketChannel) key.channel();
                        //得到一个Buffer
                        ByteBuffer buffer = ByteBuffer.allocate(1024);
                        //读取
                        sc.read(buffer);
                        //把读到的缓冲区的数据转成字符串
                        String msg = new String(buffer.array());
                        System.out.println(msg.trim());
                    }
                }
                iterator.remove(); //删除当前的selectionKey，防止重复操作
            }else {
                //System.out.println("没有可以用的通道。。");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws  Exception {

        //启动我们的客户端
        GroupChatClient chatClient = new GroupChatClient();

        //启动一个线程，每个3秒，读取从服务器发送数据
        new Thread(() -> {
            while (true){
                chatClient.readInfo();
                try {
                    Thread.currentThread().sleep(3000);
                }catch (InterruptedException e){
                    e.printStackTrace();
                }
            }
        }).start();

        //发送数据给服务器端
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()){
            String s = scanner.nextLine();
            chatClient.sendInfo(s);
        }
    }
}
